Objective
This study is aimed to evaluate a sit-to-stand (STS) pattern in the children with spastic diplegic cerebral palsy in comparison with the normal children.

Method
Fifteen young children with spastic diplegic cerebral palsy and 21 normally developed children were recruited as subjects. A motion analysis system using a Motion analyzer (Vicon 370 M.A. with 6 infrared cameras) was used to examine the STS task. The changes in joint angle, moment, and power of each joints in lower limbs, total duration of STS transfer and each transitional points were assessed.

Results
Total duration of STS in patients was 2.44 sec, which was significantly prolonged in comparing with 1.10 sec in normal control. The major prolongation of STS occurred in the phase of vertical movement of center of mass (CoM). Cerebral palsied children showed more anterior pelvic tilting and hip flexion throughout STS transfer than normal control. Asymmetries in initial angle of ankle and maximal momentum of knee extension were shown in spastic diplegic children with cerebral palsy, but not in normal control. Less extension momentum and power of knee joint and more plantar flexion momentaum of ankle joint were observed in cerebral palsy in comparing with those of normal children.

Conclusion
This study showed that STS pattern in spastic diplegic cerebral palsy was quite different from that of normal children. The characteristics of STS pattern in these children was slowness of speed; mainly from slowness of vertical displacement of CoM, and more anterior

pelvic tilt, hip flexion and earlier abrupt change of knee extension. As well, the major moments required for this task in these patients occurred at hip and ankle joints instead of knee joint.